1. Field of the Invention
The present invention relates to an electronic stringed instrument such as a guitar, a mandolin, a ukulele and a shamisen (three-stringed Japanese banjo).
2. Description of the Related Art
For example, as described in Japanese Utility Model Application Laid-Open (Kokai) Publication No. 63-029193, there has been known an electronic guitar in which the main body of the guitar is constituted by a body and a neck, and a plurality of musical trigger strings are strung over the body, and fret strings whose number is equal to the number of musical trigger strings are strung over a fingerboard provided on the neck.
In such an electronic guitar, a musical trigger switch is provided for each of the plurality of musical trigger strings which are strung over the body, and a pitch-specifying switch is provided on the fingerboard of the neck on which the plurality of fret strings are strung. The musical trigger switch is configured to detect the vibration of the musical trigger strings as an electric signal.
Also, the pitch-specifying switch includes a rubber sheet which includes a plurality of fret sections along the direction where the fret strings are strung, an electrically conductive sheet provided on the lower surface of the rubber sheet, a spacer sheet provided on the lower surface of the electrically conductive sheet, and a wiring board which is provided on the lower surface of the spacer sheet and includes a plurality of contact electrodes.
Accordingly, the pitch-specifying switch is configured as follows: the fret string is pushed with a finger and thereby pushes down the rubber sheet positioned between the fret sections, whereby the rubber sheet is elastically deformed. As a result, the electrically conductive sheet is pushed down, and comes into contact with the contact electrodes of the wiring board through the opening portion of the spacer sheet. The contact of the electrically conductive sheet with the contact electrodes allows the contact electrodes to be conducted to each other, whereby the pitch in accordance with the position of the string to be pressed is outputted as an electric signal.
In such an electronic guitar, when a performer picks with fingers the plurality of musical trigger strings which are strung over the body while holding with fingers the plurality of fret strings which are strung over the fingerboard of the neck, the pitch-specifying switch on the fingerboard outputs the pitch in accordance with the position of the string to be pressed as the electric signal, and the musical trigger switch on the body outputs the string vibration of the musical trigger string as the electric signal, thereby generating musical sound with the specified pitch in accordance with the string vibration.
However, in such an electronic guitar, a musical trigger string and a fret string are separated which are formed with a consecutive string in the case of a conventional guitar because the plurality of musical trigger strings are strung over the body and whereas the plurality of fret strings are strung over the fingerboard provided on the neck. As a result, when a performer picks the musical trigger strings with the finger for performance while holding the fret strings with the fingers, the string vibration of the musical trigger strings is not transmitted to the fret strings. Accordingly, there is a problem such as a sense of incongruity during the performance.
That is, in this electronic guitar, when a performer plays the electronic guitar, the fret string held with the finger and the musical trigger string picked with another finger may become misaligned. As a result, the fret string and the musical trigger string cannot be kept on a straight line, whereby the string vibration of the musical trigger string cannot be transmitted to the fret string. Accordingly, there is a problem in that erroneous musical sound is generated, when the performer plays the electronic guitar without being aware of the misalignment of the fret string and the musical trigger string.
Also, in this electronic guitar, a performer holds with fingers the fret string which is strung over the fingerboard of the neck and whereby the rubber sheet of the pitch-specifying switch is elastically deformed and pushed down. As a result, a performer has to press the fret strings with a strong force in order to steadily hold the fret strings with the fingers. Accordingly, there is a problem such as poor operability in terms of the strings, in addition to the sense of incongruity during the performance.
Thus, in order to solve the aforementioned problems, there has been examined an electronic guitar configured as follows: a plurality of strings having conductivity are strung over the body and the neck of the guitar body in a consecutive form, without being separated into the plurality of musical trigger strings and the plurality of fret strings. A plurality of frets of the pitch-specifying switch are formed of metal. When the plurality of strings are pressed in a state where a current flows through the plurality of strings, the plurality of strings are conducted to any of the plurality of frets, and the pitch is detected.
However, in this electronic guitar, it is necessary to enhance the intensity of the entire electronic guitar because the tension of each of the plurality of strings is increased. Accordingly, it is necessary to form a bridge section, to which one end portion of each of the plurality of strings is attached, with metal having high intensity. When the bridge section is formed of metal, there is a problem in that the plurality of strings are conducted to each other, the pitch cannot correctly be detected, and the correct musical sound cannot be generated.